Budesonide is a synthetic corticosteroid which has been effective for the treatment of inflammatory diseases of the gastrointestinal tract such as Crohn's disease and ulcerative colitis. The chemical name of budesonide is The chemical name for budesonide is 16,17-(butylidenebis(oxy))-11,21-dihydroxy-, (11-β,16-α)-pregna-1,4-diene-3,20-dione, and its chemical structure is shown as below:

Budesonide is commercially available in United States as a capsule composition ENTOCORT® EC for the treatment of mild to moderate active Crohn's disease and the maintenance of clinical remission of mild to moderate Crohn's disease involving the ileum and/or the ascending colon. ENTOCORT® EC is available as a 3 mg capsule and the recommended dosing is 9 mg orally taken once daily i.e. 3 capsules taken orally at a time. Treatment of inflammatory diseases of gastrointestinal tract requires targeted drug delivery to the small intestine and colon.
U.S. Pat. No. 5,643,602 discloses a composition comprising a non-pareil seed coated with first layer of a glucocorticoid and a film forming water insoluble polymer or water soluble polymer. Compositions used to layer the glucocorticoid on the non-pareil seed are known to form a film coating because the proportion of the film forming polymer in such composition is high. This layer is further coated with anionic carboxylic polymer like acrylic acid polymers. The patent particularly exemplifies budesonide in the working examples and prepares sustained release capsules comprising 0.5 to 2 mg of budesonide.
The present inventors have found that release of water insoluble drug such as budesonide can be controlled even when instead of forming a film coating such as that disclosed in U.S. Pat. No. 5,643,602, one forms a matrix layer containing a sugar and water insoluble polymer in a ratio greater than 3:1. This finding was surprising in view of the water solubility of the sugar which was the major component of the novel matrix layer. The sugar matrix layering composition was found useful in layering a higher load of budesonide particles per inert core and thus reduced the weight of the composition that needed to be filled into capsule. Even 9 mg budesonide could be formulated as a sustained release coating over the inert cores and the coated cores conveniently filled into single size 1 capsule. The present invention is also useful in providing a single unit dosage form such as one capsule containing the daily dose of budesonide in contrast to the marketed product Entocort® EC where 2 or 3 capsules may be required to be ingested by the patient.